Clinical outcomes of patients with heart failure with improved ejection fraction after acute MI: a multicenter prospective study from the COREA-AMI Registry

Abstract Background The 2021 Universal Definition of Heart Failure introduce a new classification, heart failure with improved ejection fraction (HFimpEF). As yet, little is known about the long-term clinical outcomes of patients with HFimpEF after acute myocardial infarction (AMI). Methods From a multicenter, prospective cohort of AMI patients undergoing PCI, patients with an initial echocardiogram at the time of PCI and at least one follow-up echocardiogram one month to two years after the initial event were considered for analysis. HFimpEF was defined as initial left ventricular ejection fraction (LVEF)≤40% and at least one follow-up LVEF>40% with an increase of ≥10% from baseline. Persistent HFrEF was defined as LVEF ≤40% without interval improvement. Patients with LVEF>40% were defined as having preserved LVEF. The primary endpoint was all-cause mortality. Results In total, 3038 patients with repeated echocardiogram measurements were selected for initial analysis. 187 patients were identified as having HFimpEF, 190 patients had persistent HFrEF, 631 patients had HFmrEF, and 2030 patients had preserved EF. Kaplan-Meier analysis revealed that HFimpEF was associated with improved survival compared to chronic HFrEF, but inferior to preserved LVEF (log-rank p<0.001). Even after multivariate Cox regression analysis was done to account for confounding variables, HFimpEF was associated with reduced mortality compared to persistent HFrEF (HR 0.49, 95% CI 0.31-0.78). Compared to patients with preserved LVEF, HFimpEF patients had a tendency toward higher mortality, but did not reach statistical significance (HR 1.18, 95% CI 0.80-1.76). Conclusion HFimpEF is associated with decreased all-cause mortality compared to persistent HFrEF in patients with AMI.